Invasive lionfish are threatening native fish and the environment in U.S. Atlantic coastal waters, including in the Florida Keys

With distinctive reddish and white stripes, gracefully flowing fins, and menacing spines, few fish embody the beauty, mystery, and danger of the ocean quite like the lionfish.

The venomous, elongated dorsal, pelvic, and anal spines of a lionfish are primarily defensive, delivering a painful sting and deterring potential predators (including humans). And while we have yet to discover who eats them, over 50 species of fish and invertebrates such as shrimp are typically on the lionfish’s menu. Lionfish have been known to swallow whole prey twice their length.

Lionfish can reach lengths of up to 20 inches and may live for as long as 15 years. They become sexually mature in less than a year and a single female can spawn over two million eggs each year. Larvae can hitch rides on ocean currents, quickly traveling great distances. All this can add up to a lot of lionfish.

Although native to the Indo-Pacific region, lionfish were introduced to the Atlantic and are now found along the U.S. coast from North Carolina to Florida and in the Bahamas and Caribbean.

Far from home, lionfish aren’t welcome.

The lionfish’s lack of predators, voracious appetite, rapid reproduction, and fast growth spell trouble for the balance of invaded ecosystems and fisheries, as lionfish can out-compete native species for food and space. Imagine a coral reef with nothing but lionfish – it isn’t quite as pretty, or healthy, as a reef filled with a variety of colorful fish.

In Florida Keys National Marine Sanctuary, divers are being encouraged to remove as many lionfish as possible. The sanctuary recently co-hosted a series of lionfish roundups, with the Reef Environmental Education Foundation (REEF) offering cash and prizes for divers bringing in the biggest catches. The derbies also educated divers on how to safely handle – and eat – these marine invaders.